added Iterables::repeatable()

Author: dg

src/Utils/Iterables.php

@@ -178,6 +178,31 @@ public static function mapWithKeys(iterable $iterable, callable $transformer): \
 	}
 
 
+	/**
+	 * Creates a repeatable iterator from a factory function.
+	 * The factory is called every time the iterator is iterated.
+	 * @template K
+	 * @template V
+	 * @param  callable(): iterable<K, V>  $factory
+	 * @return \IteratorAggregate<K, V>
+	 */
+	public static function repeatable(callable $factory): \IteratorAggregate
+	{
+		return new class ($factory) implements \IteratorAggregate {
+			public function __construct(
+				private $factory,
+			) {
+			}
+
+
+			public function getIterator(): \Iterator
+			{
+				return Iterables::toIterator(($this->factory)());
+			}
+		};
+	}
+
+
 	/**
 	 * Wraps around iterator and caches its keys and values during iteration.
 	 * This allows the data to be re-iterated multiple times.
@@ -186,7 +211,7 @@ public static function mapWithKeys(iterable $iterable, callable $transformer): \
 	 * @param  iterable<K, V>  $iterable
 	 * @return \IteratorAggregate<K, V>
 	 */
-	public static function memoize(iterable $iterable): iterable
+	public static function memoize(iterable $iterable): \IteratorAggregate
 	{
 		return new class (self::toIterator($iterable)) implements \IteratorAggregate {
 			public function __construct(

tests/Utils/Iterables.repeatable().phpt

@@ -0,0 +1,43 @@
+<?php
+
+/**
+ * Test: Nette\Utils\Iterables::repeatable()
+ */
+
+declare(strict_types=1);
+
+use Nette\Utils\Iterables;
+use Tester\Assert;
+
+require __DIR__ . '/../bootstrap.php';
+
+
+$counter = 0;
+$repeatable = Iterables::repeatable(function () use (&$counter) {
+	$counter++;
+	yield 'a' => 1;
+	yield 'b' => 2;
+	yield 'c' => 3;
+});
+
+// First iteration
+Assert::same(
+	['a' => 1, 'b' => 2, 'c' => 3],
+	iterator_to_array($repeatable),
+);
+Assert::same(1, $counter);
+
+// Second iteration - factory should be called again
+Assert::same(
+	['a' => 1, 'b' => 2, 'c' => 3],
+	iterator_to_array($repeatable),
+);
+Assert::same(2, $counter);
+
+
+// Test with empty iterator
+$repeatable = Iterables::repeatable(fn() => new EmptyIterator);
+Assert::same(
+	[],
+	iterator_to_array($repeatable),
+);